SUMMARY.

1.  Water is the only thing that will satisfy thirst.

2.  In going through our bodies, water washes out many impurities.  We also need water to soften our food.

3.  The purest water is the best.  Impure water causes sickness.

4.  Good water has no color, taste, or odor.

5.  Tea and coffee are not good drinks.  They are very injurious to children, and often do older persons much harm.

6.  Alcohol is made by fermentation.

7.  Pure alcohol and strong liquors are made by distillation.

8.  Alcohol is not a food, it is a poison.  It kills plants and animals, and is very injurious to human beings.

9.  Even the moderate use of alcoholic drinks produces disease and shortens life.

CHAPTER VII.

HOW WE DIGEST.

1. Did you ever see a Venus’s fly-trap?  This curious plant grows in North Carolina.  It is called a fly-trap because it has on each of its leaves something like a steel-trap, by means of which it catches flies.  You can see one of these traps in the picture.  When a fly touches the leaf, the trap shuts up at once, and the poor fly is caught and cannot get away.  The harder it tries to escape, the more tightly the trap closes upon it, until after a time it is crushed to death.

[Illustration:  VENUS’S FLY-TRAP.]

2. But we have yet to learn the most curious thing about this strange plant, which seems to act so much like an animal.  If we open the leaf after a few days, it will be found that the fly has almost entirely disappeared.  The fly has not escaped, but it has been dissolved by a fluid formed inside of the trap, and the plant has absorbed a portion of the fly.  In fact, it has really eaten it.  The process by which food is dissolved and changed so that it can be absorbed and may nourish the body, is called digestion (di-ges’-tion).

3. The Venus’s fly-trap has a very simple way of digesting its food.  Its remarkable little trap serves it as a mouth to catch and hold its food, and as a stomach to digest it.  The arrangement by which our food is digested is much less simple than this.  Let us study the different parts by which this wonderful work is done.

[Illustration:  THE DIGESTIVE TUBE.]

4.  The Digestive Tube.—­The most important part of the work of digesting our food is done in a long tube within the body, called the digestive tube or canal.

5. This tube is twenty-five or thirty feet long in a full-grown man; but it is so coiled up and folded away that it occupies but little space.  It begins at the mouth, and ends at the lower part of the trunk.  The greater part of it is coiled up in the abdomen.